<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>多元素</title>
    <style>
        .big{
            width: 800px;
            height: 600px;
            border: 3px solid black;
            margin: 0 auto;
            display: flex;
            justify-content: space-around;
        }
        .small{
            width: 150px;
            height: 150px;
            border: 3px solid red;
            font-size: 50px;
            text-align: center;
            line-height: 150px;
        }
        .three{
            align-self:flex-end;
        }
    </style>
</head>
<body>
    <div class="big">
        <div class="small">one</div>
        <div class="small">two</div>
        <div class="small three">three</div>
        <div class="small">four</div>
    </div>
</body>
</html>